I know a lot of people who dislike Twitter; the interface is a little wonky, the feed becomes unbearably difficult to follow and tons of useless ads. Also, the endless retweets of subjects and people that probably disgusts you flood your feed with even more junk. How can you clean this up? How can you turn Twitter into a more manageable, meaningful tool? The key is the list feature.
Twitter list are nothing more than your standard bookmark tool. Essentially, you can use it to organize the people you want to follow into more meaningful categories. The data they provide is the same as what you see in your feed. It might take some work to navigate to a list but there is a HUGE benefit in using a list over following an account: you will not see ads in your list feed (at least not yet).
My rule of thumb generally is to only Follow accounts that will follow you back and/or people you really enjoy seeing frequently as a matter of bundled convenience. In the case of reciprocal follows, I think if you some day intend to have a private conversation using Twitter with another person, then you practically need to be mutually following each other, unless the other user opens up receiving messages (which generally is bad for more private type of accounts).
Also, I think it’s a matter of etiquette where people ought to follow you back for the most part. Obviously, this isn’t the case for everyone such as a celebrity or business accounts that do not exist for interaction. But users with a smaller basis should have the courtesy on average of following you back if you share mutual interests that you perhaps want to have more conversations on. That helps both of you in providing that social currency.
However, I do think spammy/annoying accounts are better off in a list. It might seem odd to even bothering dealing with those types of accounts in the first place. But occasionally those accounts might have useful information that you have to weed through, making them great candidates for lower volume lists. That way, if you really need to see what those accounts are saying, you can just pop open your list and wad through their conversations for pertinent information.
I think a good rule of thumb is to keep the total number of accounts in a list to around 20-30, unless there’s an individual or two that has a high volume of tweets. The same rule should apply to your follower list just to make your feed more visually sane. It might not seem as active over time, but you’ll eventually determine which list are the most important to you. So you’ll save time in the long run.